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Panther Series - CGS758 Utility LFO 

Construction of the CGS758 is 
straightforward. There are 2 
main boards, one for each LFO, 
and these are built identically 
except for the 3 jumper/links 
(J101, J102 & J 103) which are 
wired in opposite positions 
between the 2 boards ie one 
board (which will hold the SWAP 
switch) has wire links fitted in 
positions 1-2 on all 3 
jumper/links while the other 
board (which will hold the JOIN 
switch) has wire links fitted in 

positions 2-3 on all 3 jumper/links. In addition to the 2 main boards, there are also 2 Panther Support boards. 

These boards provide mountings locations for the 8 jack outputs. 

Fit all components to the boards following normal assembly guidelines (see General Assembly Guide). 

When fitting the pots to the pcb please ensure that there is approximately 1mm gap between the shoulder on 
the pot pins and the top of the pcb to prevent the possibility of the shoulders shorting to adjacent pads. 

The design of the main board allows for a DPDT switch with extended (wire-wrap) legs to be used however 

builders may use a more standard DPDT switch but will need to hardwire the pins to the board. If using the 

extended wire-wrap 

version of DPDT builders 

should loose-fit the switch 

on to the board and then 

offer the assembly up to 

the front panel and tighten 

up the pot nuts to hold the 

assembly firmly to the 

panel. Ensure that the 

board is sitting reasonably 

perpendicular to the panel 

and then move the switch 

in to position and fit and 

tighten its nut. Solder the 

pins for the switch in to 

the board. 

Only one power connector is required, 
main boards. 

it can be fitted to either of the 

The two shorter interconnect cables are used to connect the 
associated Panther Support board to the main board. The third cable 
connects to the two main boards together and provides power to the 
second LFO board as well as the inter-connections for the JOIN/SWAP 

Take special note of the orientation of the crimp housings with respect 
to the cable. 

The CGS758 does not require any calibration and should work as soon as power is applied. 

Elby Designs - Laurie Biddulph 

9 Follan Close, Kariong, NSW 2250, Australia 

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Panther Series - CGS758 Utility LFO 

CGS758 Rev 1.1 

Constructors should refer to the Component Overlay and the Bill Of Materials for the current value of all 

Note the 3 links in the top left corner which must be correctly installed depending upon the function of the 
Switch top left (SWAP or JOIN). You will need 2 of these boards for each module and one board should 
wired for SWAP whilst the other is then wired for JOIN. 

The BEAT LED (D103) needs to be formed so that it pokes through the mating hole in the front panel. Bend 
the legs to a right-angle approximately 14mm from the front face of the LED. 



Elby Designs - Laurie Biddulph 

9 Follan Close, Kariong, NSW 2250, Australia 

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Panther Series - CGS758 Utility LFO 


Operation of the unit can be performed by connecting the various outputs to a modulation input of a VCO or 
an oscilloscope. 

Set both the JOIN and SWAP positions to their upper setting. This disconnects the two LFO's and 

allows them to run, and be used, as two independent modules. 

Set all pots to minimum. 

Connecting, in turn, to each of the three waveform outputs you should be able to observe the 

appropriate waveform (Pulse, Saw/Tri and Square). Increase the SPEED control and observe the 

increase in frequency. 

The LED indicator should beat in time with the frequency and, being connected to the SAW/TRI 

output, will change in intensity as it follows the slope of the waveform. 

Connect to the SAW/TRI output and set the SPEED control to a position that allows you to easily 

observe the shape of the waveform. 

Adjust the SHAPE control. You should be able to observe the output start from a falling ramp at the 

minimum position of SHAPE, transform in to a symmetrical triangle waveform at the mid-position of 

the SHAPE control and finally transform in to a rising ramp at the maximum position. 


• Connect to the VARI1 output. This is best done with an oscilloscope but can be done with a VCO if 
the SPEED control is set to a fairly low setting. 

• Set the SAW/TRI to its mid-position. 

• With the VARI1 control at its minimum position you should observe a square wave output. Sweep 
the VARI control to maximum and you should observe the output provide an increasing mix of the 
SAW/TRI output with the mix being 50-50 at the midpoint and reducing to a full SAW/TRI waveform 
at the maximum position. 

Repeat these steps for the VARI2 output. 

The Panther Series of modules have been designed to be 
compatible with the popular Doepfer range of EuroRack 
modules and consequently uses a matching connector. 

The red stripe on the power cable represents pin 1 (-12V 
rail) on the IDC connector. 

All Panther Series 
boards used a boxed 
16-way IDC header 
with a polarising key. 
Pin 1 on the power 
connector is towards 
the centre of the board. 

Please pay particular attention to the orientation of the power cable 
and connector to prevent possible damage to the system. 

Elby Designs - Laurie Biddulph 

9 Follan Close, Kariong, NSW 2250, Australia 

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